Omron CJ1W-CLK21-V1 ユーザーズマニュアル

Data link communications will continue, so the Communications Error Flag for
the data link status will not turn ON in any of the nodes in the network.

Refer to 

 for details on timing required to change the data link

tables.

When changing data link tables with active data links, the data refresh for the
corresponding node will stop temporarily. During that time, even if the data in
the data link send area in the PLC is refreshed, it will not be sent as data link
data to other nodes. Data received from other nodes will also not be shown in
the data link receive area of nodes with data link tables that are being
changed. The data refresh interrupt timing (maximum theoretical value) is as
follows:

Data link refresh maximum interrupt time = 2 

×

 Unit cycle time of the node

with data link table being changed (See note 1.) + 3 

×

 communications cycle

time (ms)

1.

When CS- or CJ-series PLCs are being used, if the total number of data
link send words exceeds 7,800 words, this value is multiplied by 3.

2.

Consider the effect of the data link refresh interrupt time on the applica-
tions when changing the data link tables. If the maximum interrupt time is
not suitable for the user application, transfer the data link table after stop-
ping the data links from a Programming Device as before, and then restart
the data links.

Command re-
ceived to change 
with active data 
links

Change during 
active data links 
completed

Time

Data link send data

Data link receive data

Most recent data read from 
Unit

Data immediately 
before change

Most recent data read from 
Unit.

Most recent data received 
from other node

Data immediately 
before change

Most recent data received from 
other node

Refresh stopped

Refresh resumed

Data link area of node with the data link table 
to be changed